Accession Number : ADA137087

Title :   Some Preliminary Theoretical and Experimental Studies on Undulated Open Tubular Flow Paths.

Descriptive Note : Final rept. Apr-Nov 81,


Personal Author(s) : Rubey,W A ; Krishnamurthy,L ; Dirkes,W E , Jr

PDF Url : ADA137087

Report Date : Sep 1982

Pagination or Media Count : 92

Abstract : Investigations were conducted to evaluate the fluid dynamic behavior of flows in undulated open tubes (UOT). The UOT concept was evaluated to determine whether it could be used to improve the performance of gas chromatography which is an analytical technique that is used to separate, identify, and quantitate components of complex mixtures such as jet fuels. Gas chromatographic data is usually displayed as signal strength plotted retention time. The individual compounds in the mixture are separated into solute zones in the gas chromatographic column which are represented as peaks on the data plot. Gas chromatographic performance is improved by decreasing the width of the individual peaks, increasing the separation between neighboring peaks, and increasing the amount of sample which can be injected without causing peak distortion. In general, gas chromatograph design requires compromise among these three goals. The focus of this effort was to determine whether a UOT could allow narrower peaks (reduced solute zone dispersion) and larger sample capacities than state-of-the-art capillary columns. A UOT is circular in cross-section but the diameter decreases then increases in a repetitive manner along the length of the tube, producing a repetitive nozzle/diffuser flowpath. Experiments showed that the UOT samples evaluated did not display improve chromatographic performance when compared with state-of-the-art chromatographic columns.

Descriptors :   *Gas chromatography, *Fluid flow, Solutes, Flow visualization, Column chromatography, Tubes, Metals, Glass, Drawing(Forming), Cross sections, Constants, Experimental data, Peak values, Fluid dynamics, Gas flow, Mass flow, Rates, Density

Subject Categories : Physical Chemistry
      Test Facilities, Equipment and Methods
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE